5 1 2 FISHES CHAP. 



the great African continent, ranging from the river Senegal and the 

 Wliite Nile on the north to the Congo basin, Lake Tanganyika, and 

 the Zambesi on the south. Three species are known, P. annectens 

 (Fig. 304), P. aethiopicus, and P. clolloi. Protojjterus ^ is usually 

 found in marshes in the vicinity of rivers. Voracious in its habits 

 the Fish is mainly carnivorous, subsisting principally on Frogs, 

 worms, insects, and crustaceans. It is by no means averse to 

 preying upon its own kind, and if several of these Fishes are 

 confined in the same aquarium they are apt to give free vent 

 to their cannibal instincts by biting off the tails or limbs of their 

 fellows. The missing parts are soon regenerated, but the new 

 members are usually somewhat abnormal, the tail, for instance, 

 never regaining its original length, while a new pectoral limb 



Lepidosiren. Protopterus. JVeoceratodus 



Fig. 306. — Map showing the distribution of the surviving Dipneusti. 



may be bifid or even trifid.- The tail is the principal organ 

 of locomotion, and by its means the Fish is capable of remarkably 

 quick, agile movements. When slowly moving over the bottom 

 of an aquarium the paired limbs are observed to move to and 

 fro on opposite sides alternately in a somewhat bipedal fashion. 

 The limbs are useless for swimming, although it is possible that 

 they may be helpful in creeping over the bottom, or in balancing, 

 or as tactile organfe. Protopterus is said to breathe by its lungs 

 as well as by its gills, and to rise to the surface at short intervals 

 to take in fresh air. In the dry seasons the marshes in which 

 Protopterus lives become dried up, and to meet this adverse 



' For a list of the more important papers on Protopterus, see Boulenger, Les 

 Poissmis du Bassin du Congo, Bruxelles, 1901, pp. 40-42. 



- Traquair, Rep. Brit. Ass. 1871 (2), p. 143 ; Boulenger, P.Z.S. 1891, p. 147. 



